The prior art is already aware of the method and apparatus of conveying a sheet, such as paper in a signature form, for instance, along a conveyor system which either changes the orientation of the sheet from a front-leading edge to a side-leading edge, that is, turns the sheet at a right angle. Also, the prior art is aware of the conveyor system and method whereby sheets are turned in a ninety degree or so arc but the front edge is always the front or leading edge in the path of movement of the sheet. That is, in the first aforesaid example of the prior art, one conveyor leads the sheet in a forward direction and against a stop, where the sheet is intercepted and is then placed onto a second conveyor, which leads the sheet in a sidewise direction so that the sheet then has its side edge become its leading edge. In the aforesaid second example of the prior art, a conveyor with a ninety degree arc is utilized and the sheet simply moves through that ninety degree ard, but its initial leading edge is also its final leading edge while the sheet traverses the ninety degree arc. Those skilled in the graphic arts industry are already familiar with that type of sheet movement and orientation for purposes of presenting a sheet to other apparatus for collating or other functions common in the art. Prior art showings of conveyor systems and methods for transporting a product and governing the leading edge of the product are shown in U.S. Pat. Nos. 914,832 and 3,160,259 and 3,191,747 and 3,323,425 and in British Pat. No. 1,239,334. Those prior art showings differ from the present invention in both the method in apparatus in that the present invention provides a system for controlling the leading edge of a sheet while the sheet is being conveyed along a path, such that either the leading edge remains as the leading edge throughout that conveyance, or the sheet is turned so that its initial front or leading edge is no longer the leading edge but instead the side edge of the sheet becomes the new leading edge. Further, in the prior art method and apparatus, separate apparatus and systems are required for either the side movement of the sheet, as mentioned and described herein, or for the acruate or ninety degree turn movement. In the present invention, only one system or one set of apparatus is required, and either the side movement or the turning movement can be effected, by the operator's choice of using the apparatus or employing the appropriate method of this invention.
Accordingly, the present invention provides a system whereby the system can be operated and a mode for either the so-called bump turn or sidewise sheet movement, or for the ninety degree arcuate turn movement, all at the option of the operator. In accomplishing this objective, only one set of apparatus is required, and it can be placed in either mode of operation by manipulation of parts of the apparatus. In the specific method in apparatus of this invention, a set of conveyor belts is utilized for conveying a sheet, and drive members are related to the individually driven belts so that the belts can move at either the same speed, for the so-called bump turn mode, or the belts can be operated at speeds wherein each belt operates at a different speed, and thus the arcuate flow turn mode is accomplished.